UNIVERSITY   OF   CALIFORNIA 

COLLEGE    OF   AGRICULTURE 

AGRICULTURAL   EXPERIMENT  STATION 

CIRCULAR  No.  249 
June,  1922 

REPLACING  MISSING  VINES 

By  FREDERIC  T.  BIOLETTI 


Regularity  of  the  vineyard  is  essential  to  economical,  maximum 
production  of  the  best  grapes.  Two  necessary  factors  of  regularity 
are  a  perfect  ''stand"  and  even  size  and  vigor  of  the  vines;  that  is, 
every  vine  should  be  growing  and  should  be  equally  capable,  under 
the  same  treatment,  of  bearing  grapes  in  competition  with  its  neigh- 
bors. 

The  best  way  to  reach  this  condition  is  to  develop  a  perfect  stand 
of  even  vines  the  first  year,  a  degree  of  perfection  seldom  reached 
even  by  the  most  skilful  and  experienced  growers.  If  95  per  cent 
of  the  vines  planted  grow  it  is  considered  excellent ;  85  per  cent  is 
nearer  the  average  even  in  good  vineyards ;  and  much  lower  per  cents 
are  common. 

Where  vines  are  missing  the  first  year,  new  vines  are  planted 
the  second.  The  cost  of  planting  these  vines  is  high,  they  are  more 
troublesome  to  take  care  of,  they  grow  less  vigorously,  and  a  larger 
proportion  of  them  fail.  After  the  second  year,  replanting  becomes 
increasingly  difficult  and  uncertain.  Replants  after  the  second  year 
are  always  dwarfed  and  many  growers  doubt  whether  they  pay  for 
the  work  they  make.  Some  growers  believe  that  the  loss  from  a 
missing  or  dwarfed  vine  is  made  up  by  increased  crops  on  the  adjoin- 
ing vines.  The  compensation  for  a  dwarfed  vine  is  in  whole  or  part 
neutralized  by  the  cost  of  handling  a  small  vine,  which  is  nearly  as 
great  as  that  of  a  large  one.  Moreover,  irregularity  in  the  size  of  the 
vines  increases  the  cost  and  difficulty  of  proper  pruning  and  culti- 
vation. 

The  extent  of  the  compensation  for  missing  vines  may  be  estimated 
from  observations  made  in  the  experiment  vineyards  at  Kearney  and 
at  Davis. 


2  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 

Muscat  (144  vines  five  years  old)  at  Kearney — Crops  of  1915-16: 

Mean  crop  of  vines  between  two  vines 27.8  lbs. 

Mean  crop  of  vines  next  to  a  vacancy 30.6  lbs. 

Mean  crop  of  vines  at  end  of  rows 30.7  lbs. 

Sultanina  (240  vines  seven  years  old)  at  Davis — Crops  of  1916-17  : 

Mean  crop  of  vines  between  two  vines 28.6  lbs. 

Mean  crop  of  vines  next  to  a  vacancy 34.8  lbs. 

This  indicates  that  the  loss  of  27.8  lbs.  due  to  a  missing  Muscat 
was  partially  made  up  by  an  extra  crop  of  5.6  lbs.  on  the  two  neigh- 
boring vines,  a  compensation  of  about  20  per  cent.  The  loss  of  28.6 
lbs.  due  to  a  missing  Sultanina  was  compensated  to  the  extent  of 
12.4  lbs.,  or  about  43  per  cent. 

With  weak  varieties  the  compensation  is  less  because  they  are 
less  capable  of  utilizing  the  extra  space.  For  a  similar  reason  the 
wider  the  spacing,  the  less  the  compensation.  The  compensation  will 
undoubtedly  increase  as  the  vines  become  older  but  will  probably 
never  be  complete  unless  the  vines  are  planted  much  too  close.  Where 
two  or  more  vines  are  missing  in  adjoining  spaces,  the  compensation 
will  of  course  be  less. 

If  we  accept  the  results  of  the  weighings  at  Davis  and  Kearney 
as  typical,  the  loss  on  a  Muscat  vineyard  with  a  normal  crop  of  6  tons 
per  acre  is  about  960  lbs.  per  acre  for  every  10  per  cent  of  missing 
vines,  and  about  680  lbs.  in  a  similar  Sultanina  vineyard. 

The  loss  from  the  dwarfed  vines  that  result  from  most  replanting 
and  the  corresponding  compensation  from  their  overgrown  neighbors 
can  only  be  estimated.  Both  loss  and  compensation  would  probably 
be  less  than  with  missing  vines,  though  possibly  the  net  loss  would 
be  nearly  or  perhaps  quite  as  great,  if  we  consider  the  cost  of  handling 
the  small  vines. 

In  some  cases  it  is  possible  to  replant  missing  vines  perfectly  at 
any  age  by  the  method  of  layering.  This  can  be  done  easily  only 
in  a  trellised  vineyard.  Two  ways  of  applying  this  method  in  an 
Emperor  vineyard  grown  on  the  cordon  system  are  shown  in  the 
photographs. 

Photograph  A  shows  a  long  vigorous  cane  (c)  reserved  for  the 
purpose  on  a  vine  adjoining  the  vacant  space  (o).  This  cane  is  to 
be  placed  in  the  ground  as  soon  as  the  conditions  for  growth  are 
favorable,  late  in  March  or  in  April.  Two  ways  of  doing  this  are 
shown  by  photographs  B  and  C. 


Circular  249] 


REPLACING    MISSING    VINES 


TIT 


Replanting  a  cordon  by  layering.    A,  cane  (C)  reserved  for  layering;  B,  direct 
layer — growth  the  first  year  (NV) ;  C,  reversed  layer — growth  the  first  year  (NV). 


4  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION 

In  the  case  shown  by  B  the  reserved  cane  (w)  was  bent  down  to 
a  trench  about  10  inches  deep  and  carried  along  the  bottom  of  this 
trench  to  the  place  of  the  missing  vine.  There  it  was  bent  up  at  a 
sharp  angle  and  tied  to  the  stake,  where  it  was  cut  off,  leaving  only 
one  bud  above  the  ground.  N  V  is  the  new  cane  which  grew  from  this 
bud  during  the  first  summer.  It  is  larger  than  the  original  cane  and 
reaches  well  beyond  the  next  vine. 

In  the  case  shown  by  C  the  reserved  cane  (w)  was  simply  cut  to  a 
suitable  length  and  planted  in  a  reversed  direction  in  the  place  of 
the  missing  vine.  The  new  cane  (N  V)  which  grew  the  first  year  is 
strong  and  healthy  but  smaller  and  less  vigorous  than  that  of  case  B. 

The  method  shown  by  B  gives  the  best  results.  A  reversed  layer 
should  be  used  only  when  it  is  impossible  to  get  a  cane  sufficiently 
long  for  a  direct  layer.  The  direct  layer  gives  a  better  shaped  trunk 
and  develops  more  rapidly.  The  reversed  layer  will  make  more  growth 
the  first  year  if  a  wire  (w)  is  placed  around  the  cane  just  behind  the 
bud  that  it  is  desired  to  develop.  As  the  cane  increases  in  thickness, 
the  pressure  of  this  wire  prevents  the  passage  of  food  from  the  leaves 
into  the  old  vine  and  directs  it  into  the  roots  of  the  new  vine.  The 
original  cane  will  then  remain  small  as  in  B,  instead  of  increasing  as 
shown  in  C. 

The  only  care  needed  by  these  layers  during  the  growing  season 
is  to  prevent  all  growth  on  the  layered  cane  except  the  single  shoot 
reserved  for  a  new  vine  and  to  carefully  tie  up  this  cane  to  give  it 
the  desired  form.  No  buds  should  be  allowed  to  grow  on  the  cane 
between  the  nurse  vine  and  the  ground. 

The  new  vine  is  separated  from  the  nurse  vine  after  the  second 
year's  growth.  With  the  direct  layer,  the  separation  is  made  below 
ground  at  the  point  indicated  by  an  arrow;  with  the  reversed  layer, 
at  the  points  indicated  by  the  dotted  lines. 

The  new  vine  produced  from  a  layer  should  be  allowed  to  bear 
little  or  no  fruit  the  first  year  and  the  crop  should  be  limited  the 
second  year.  The  vine  is  thus  enabled  to  devote  all  its  energies  to 
growth  of  stem  and  root  and  by  the  third  year  it  will  be  able  to  com- 
pete with  its  older  neighbors  on  equal  terms. 


